Method of agitating cleansing liquid



June 27, 1961 M. R. BLAND METHOD OF AGITATING CLEANSING LIQUID 4 Sheets-Sheet 1 Filed July 25, 1958 IN VEN TOR.

ATTO R N 5Y5 June 27, 1961 M. R. BLAND 2,990,302

METHOD OF AGITATING CLEANSING LIQUID Filed July 25, 1958 4 Sheets-Sheet 2 F/ UE MARSHALL R. BLAND INVENTOR.

ATTORNE V5 June 27, 1961 M. R. BLAND 2,990,302

METHOD OF AGITATING CLEANSING LIQUID Filed July 25, 1958 4 Sheets-Sheet 3 M SHELL R. BLQND QR INVENTOR.

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ATTORNEYS June 27, 1961 M. R. BLANDI 2,990,302

METHOD OF AGITATING CLEANSING LIQUID Filed July 25, 1958 4 Sheets-Sheet 4 ATTORN EYS 90,302 METHOD OF AGITATING CLEANSING LIQUID Marshall R. Bland, La Habra, Calitl, assignor, by mesne assignments, to Purex Corporation, Ltd, a corporation of California Filed July 25, 1958, Ser. No. 751,079 7 Claims. ((31. 134-10) This invention relates generally to improved methods of cleaning soils from parts inserted within a liquid receptacle containing liquid subject to mechanical agitation. More particularly the invention concerns methods of propelling the liquid in relation to side recesses in the receptacle so as to displace and guide the liquid flow in high velocity cleansing relation with soiled articles placed centrally within the receptacle.

In the past, cleansing apparatus of the general type referred to was operable to agitate liquid in a continuous unidirectional flow pattern and below soiled parts placed within the receptacle. While some improvement in cleaning efiiciency resulted from the use of such known apparatus, it was found that the degree of improvement was low in relation to the amount of mechanical energy imparted to the liquid by the agitating means. Having this in mind, it is a major object of the present invention to provide a method of displacing cleaning liquid in a receptacle in such a way that the soils removing efiicieney of the displaced solution or liquid will be greatly improved in relation to the amount of energy imparted to the liquid.

In carrying out the above object, the invention contemplates displacement of the liquid within the receptacle in such manner that it moves with high velocity both tangentially and in paths normal to soil carrying surfaces of the parts to be cleaned, thereby promoting the cleansing effect, both mechanical and chemical, resulting from continuous and actively moving contact of the solution against the soils. Such high velocity directed normal impingement and tangential shearing action of the solution on the soils is secured or obtained by propelling liquid within recesses at opposite sides of the receptacle so as to draw the liquid in high velocity courses of flow from within the interior of the cleaning zone toward said recesses and so as to return the liquid in high velocity courses of flow away from the recesses toward the interior of that zone. Concurrently with such propulsion, the liquid is directed or guided in a viscous or laminar and streamlined fiow pattern everywhere along the walls of the receptacle which is shaped to receive a rectangular parts basket, to the end that there may be minimum loss of energy as reflected in loss of velocity of the liquid particularly within the rectangular parts cleansing zone wherein maximum velocity of the liquid is desired for more efiicient cleansing.

It is an important feature of the invention that the direction of liquid propulsion in the recesses is periodically reversed so as to secure a reversal in the direction of liquid displacement or flow within the cleansing zone, having the effect of alternating the liquid impingement and shearing effects on soils carried by the parts exposed to the high velocity circulating liquid through the cleansing zone. More specifically, the invention contemplates periodically reversing the direction of liquid propulsion in first one and then the other of opposite side recesses in the receptacle in order that opposite normal impingement and opposite tangential shearing action of the liquid on the soils may be realized within the cleansing zone, all as will be described.

Another important feature of the invention concerns directing the flow of liquid in the recesses in four divergent or convergent paths spaced about the central horizontal States Patent ice axis of liquid propulsion within each recess, in order that the liquid may be controllably circulated with streamline flow toward or away from the top, bottom, and two opposite sides of the receptacle, and in continuous looping pattern through the liquid cleansing zone, the direction of flow depending upon the direction of liquid propulsion at the centers of the recesses. As will appear, such controlled high velocity circulation of the liquid in loopshaped configuration increases ultimate soils cleansing efiiciency through maintenance of high velocity fiow of liquid in the cleansing zone.

Another object of the invention includes the removal of soils entrained in the circulating liquid by circulating a side stream of the liquid through a settling zone below the parts cleansing zone. Finally, the invention contemplates passing steam or other gas from the parts cleansing zone upwardly therefrom, maintaining a liquid seal above and overlying the cleansing liquid, and establishing circulation between the cleansing liquid and the liquid seal.

Other objects of the invention, as well as the details of an illustrative embodiment, will be more fully understood from the following detailed description of the drawings, in which:

FIG. 1 is a side view of one form of the cleaning apparatus showing the receptacle partly broken away to illustrate the interior construction thereof, and the flow of liquid therein;

FIG. 2 is an end elevation of the exterior of the receptacle;

FIG. 3 is a view taken on line 3-3 of FIG. 1;

FIG. 4 is a view taken in elevation showing a modified soils entrapment zone at the bottom of the tank and a perforated baffie separating that zone from the cleansing zone thereabove;

FIG. 5 is a view taken in elevation showing the battle of FIG. 4 in raised position;

FIG. 6 is a view taken in elevation showing a modified bafliing arrangement above the cleansing zone together with mechanism for moving the bafiling;

FIG. 7 is a plan view through a modified tank showing multiple screw propellers at opposite sides thereof;

FIG. 8 is a plan view of a modified rectangular tank havling screw propellers at each of the four sides of the tan FIG. 9 is a schematic elevation of the interior of a cleansing receptacle incorporating the invention and showing one flow path of liquid therein;

FIG. 10 is a view similar to FIG. 9 showing an alternate flow path of cleansing liquid;

FIG. 11 is a 'view similar to FIG. 9 showing another alternate flow path of cleansing liquid; and

FIG. 12 is still another view similar to FIG. 9 showing yet another possible flow path of the liquid.

Referring first to FIGS. 1 through 3, the cleansing apparatus 10 includes an upright tank 11 which has opposite front and rear walls 12, and opposite side walls 13 together forming an interior zone 14 for receiving articles to be cleansed. Typically, such articles may comprise jet engine parts such as illustrated at 15 as retained in a rectangular basket 16 received downwardly between the receptacle walls into the cleansing zone 14. The basket is shown as seated on a grating 17 typically having an egg-crate design and consisting of two sets of integral panels extending vertically and at right angles to one another to form spaces 18 therebetween into which soils removed from the parts 15 are adapted to settle out of the path of liquid circulation, in the receptacle.

The opposite walls 12 of the tank have recesses 19 formed therein which open transversely and divergently toward the cleansing zone 14. Each of the recesses is preferably in the form of a truncated pyramid having four divergent sides, a vertically spaced pair 20 of which diverge respectively toward the top and bottom of the receptacle. Similarly, a horizontally spaced pair 21 of the recess sides diverge respectively toward the opposite sides 13 of the receptacle, and it will be understood that as a result of this recess configuration the liquid is circulated in the tank in four loops which merge in the central regions of the cleaning zone, as indicated by the arrows in FIGS. 1 and 3.

Such liquid circulation is preferably effected by a hydrodynamically designed and reversible thrust propeller 22, typically a three blade screw propeller, operable to displace the bulk of the liquid therethrough, and alternately in axially opposite directions, as distinguished from the action of a centrifugal impeller which throws the bulk of the liquid radially therefrom during impeller rotation and moreover is not reversible to displace liquid in opposite directions as desired. Each propeller is attached to a horizontally extending shaft 23 projecting through the wall 12 at its flat square head or base 24 from which diverge the upwardly and downwardly flared wall portions 20 and the horizontally flared portions 21 of the receptacle wall 12. Attached to the base 24 is the housing 28 of an electric motor, which is preferably reversible so that the propeller 22 may be driven in opposite directions. Each of these motors may-be of the induction type, so that by changing the polarity of the motor or the phase relationship of the applied current a reversal in the direction of the drive transmitted to the propeller may be secured. Current is applied to each motor through switching mechanism indicated at 30 which is operable to reverse the direction of drive transmission to the propellers from the motors, for purposes to be described. A master switch is shown at 130.

In operation the liquid filling the tank is caused to be circulated by the opposed propellers, which have a common horizontal axis of rotation as shown in FIG. 1, such circulation being indicated by the arrows. When the propellers are rotatedso as todisplace liquid axially therethrough, the liquid flows radially in a laminar of viscous flowpattern in each of the recesses 19 adjacent the flared Wall portions 20 and 21. Since those wall portions flare outwardly to the top, bottom and opposite sides of the receptacle, the flow pattern therealong is streamlined and not turbulent. Furthermore, each propeller is spaced at a distance from the head or base 24 substantially equal to the diameter of the propeller, it having been found that this dimensional relationship is most desirable from the standpoint of the viscous or laminar flow pattern desired.

As the liquid leaves the recess 19 in the four loops indicated by the arrows in FIGS. 1 and 3, it circulates through the cleansing zone 14 in the symmetrical flow pattern shown by the arrows, which assumes that opposite propellers are being rotated to displace liquid axially therethrough toward the heads or bases 24 and away from the cleansing Zone. Such circulation is reversible by reversing the direction of propeller rotation to secure alternation of the impingement and shear effects of the flowing high velocity liquid upon the soils coating the pants to be cleaned. Also, opposite propellers may be rotated so that the liquid circulates as shown in FIG. 7, flowing completely across the tank from propeller to propeller. Under these conditions, the liquid passes through both propellers in the same direction, whereas in FIG. 1 the liquid passes through opposite propellers in opposite directions.

Shown in the upper regions of FIG. 1 and also in FIGS. 2 and 3 is a split cover or baffie 32 extending in a horizontal plane and overlying the cleansing zone 14 within the tank or receptacle. The cover halves are guided in tracks 33 so as to be slidable transversely outwardly away from the receptacle, leaving the cleaning zone exposed for downward reception of the parts basket 16.

FIG. 2 shows a plate type heating element 35 secured to the inner side of the receptacle flared wall portion 27 for heating the liquid therein to desired temperature for maximum cleaning efliciency, typical cleansing liquids consisting of trichloroethylene, cylohexane, and solutions of detergents, or acids or bases, such as strong caustic solutions. Representative soils on parts such as bearings, shafts, compressor blades, sleeves and the like include greases, oils, dust tar, sludge, rust, resin, wax, carbon, lapping and bufling compounds, and steel particles.

The tank shown in FIGS. l to 3 has a sloping bottom tapering downwardly and away from the grating 17 to form a flow space 81 within which collected soils may flow laterally to the normally closed outlet 82. Liquid is typically supplied to the tank through an inlet 8-3 in Wall 13 below the level of the cover 32.

FIG. 4 shows a cleaning tank or receptacle 11 having a cleaning zone 14 separated from a soils collection zone 54 therebelow by a perforated false bottom bathe plate 55. The latter is hinged at 56 at one side of the receptacle and supported at 57 at the opposite side of the receptacle, with the baffle plate extending horizon tally so that liquid may flow thereover with minimum resistance. Soils separating out on the bafile 55 are carried downwardly through the perforations therein into the collection zone 54 by a side stream of the flowing liquid, which then returns upwardly through plate perforations into the main stream of liquid flow in the cleansing zone, as indicated by the arrows. The baffle plate is shown in lifted position in FIG. 5, giving access to the soils collection zone for cleaning it at regular intervals, the cover 37 or" the tank having been removed.

In FIG. 6 there is shown a pair of bafiles 60 each comprising parallel metal slats 61 hinged together at 62 along their lengthwise dimensions so that the baffles may be bodily displaced between extended horizontal position overlying the cleansing zone and into vertically retracted position at opposite sides of that zone. As illustrated, the opposite ends of the slats are guided in track units 63 extending vertically and horizontally and attached to'the inner sides of the tank or receptacle walls 12. The slats may have gaps therebetween for receiving the teeth 65 of driving sprockets 66, a suitable drive system for the sprockets being provided. Typically such 'a system will include a motor 67- outside the receptacle driving a worm 68, which engages a gear 69 on a shaft 70, the latter driving the sprockets 66 through bevel gears 71. The baflies 60 illustrated are of the so-called leaking type, that is they will permit escape of gaseous pressure from the cleansing zone. Thus, should steam form therein it will escape upwardly through the baflle While at the same time the latter prevents excessive upward escape of agitated cleansing liquid from the tank during a cleansing operation. Furthermore, the bafiie system illustrated in FIG. 6 may be used for separating the liquid in the cleansing zone from a sealing liquid layer in the region above the baflie. Corrosion inhibitors such as potassium chromate in the liquid seal, which typically comprises water, may then wash slowly downwardly through the baflle into the cleansing solution, there being suflicient circulation between the latter and the liquid seal to permit such slow washing of the corrosion inhibitors into the cleansing solution.

Turning now to FIG. 7, the recessed wall of the elongated receptacle therein shown contains two recesses 19, with a propeller in each recess opposite a similar propeller in the opposite recessed wall of the receptacle. As shown, the design of the receptacle, propellers and recess walls 19 is the same as previously described, with the exception that the receptacle is much longer, accommodating an elongated parts basket 73 within which long jet parts are typically receivable. Vertical ways 74 at opposite sides of the receptacle and between the recesses at each side of the latter are adapted to receive a divider illustrated at 75 for dividing the cleansing zone and receptacle in two parts, each of which is substantially the same as viewed in FIGS. 1 through 3.

The propellers are rotatable to circulate the liquid typically as viewed in FIG. 7, so that it travels at high velocity across the tank or receptacle from propeller to propeller. Under these conditions, the liquid is displaced axially through both propellers in the same direction.

The directions of propeller rotation may be reversed at intervals to travel the liquid through both propellers in the same directions as schematically seen in FIGS. 9 and 10. Also the propellers may be rotated so that the liquid instead of passing therethrough in the same direction passes through opposite propellers in opposite directions under which conditions the liquid flow in the central regions of the tank will be turbulent due to the interference of the flow directed toward the center of the receptacle from each recessed side thereof. FIGS. 11 and 12 respectively illustrate schematically the liquid flow pattern when the liquid is passed through both propellers toward the sides of the receptacle and alternately toward the center thereof. Reverse shear and impingement flow directions of the liquid is illustrated by the arrows in the broken line sections 80 of the cleaning zones associated with FIGS. 9 through 11.

FIG. 8 shows another modified rectangular tank construction in which all four opposite sides of the receptacle are similarly oppositely recessed as at 19, with a propeller in each recess. As shown, opposite propellers 76 are rotated so as to circulate liquid axially toward the center of the receptacle, whereas opposite propellers 77 are rotated so as to circulate liquid oppositely away from the center of the tank, the resulting flow pattern comprising the four circulation loops 78. Upon reversing rotation of the pairs of propellers, the directions of the arrows designating these loops will likewise be reversed, to achieve the high efliciency alternate shear and impingement cleansing action desired.

Referring again to FIGS. 9 through 12, a typical cycle of operation will include rotation of the propellers to displace the liquid axially as seen in FIG. 9 for 2 /2 minutes, following which one of the propellers will be reversed and operation continued for another 2 /2 minutes. At the end of this time the other propeller is reversed, and finally after the end of 2 /2 minutes the first propeller is again reversed to complete the cycle. As a result, the cycle will incorporate in sequence the flow patterns illustrated in FIGS. 9, 12, 11, and involving reversal of the right side propeller at the end of every interval of 2 /2 minutes duration and reversal of the left side propeller at the end of 5 minute intervals, providing for alternating the normal impingement and tangential shear effects of the liquid on the soils, as indicated by the arrows contained within the broken line sections 80 of the cleaning zones shown in FIGS. 9 through 12. a

I claim:

1. The method of displacing liquid within a cleaning zone formed by an upright receptacle having recesses at opposite inner sides thereof opening oppositely toward one another transversely of and across said zone, said method improving the effectiveness of soils separation from solid articles placed in said cleaning zone, that includes propelling liquid to flow both axially centrally and transversely of said recesses and through propulsion zones in the recesses so as to draw liquid in first high velocity courses of fiow from within the interior of said cleaning zone toward said recesses and so as to return liquid in second high velocity courses of flow away from said recesses toward the interior of said cleaning zone, directing the propelled liquid in streamlined flow pattern looping toward the interior of said cleaning zone from about said propulsion zones, and periodically reversing the directions of liquid propulsion in first and second recesses at the ends of predetermined primary and secondary time intervals respectively.

2. The method of displacing liquid within a cleaning zone formed by an upright receptacle having recesses at opposite inner sides thereof opening oppositely toward one another transversely of and across said zone, said method improving the effectiveness of soils separation from solid articles placed in said cleaning zone, that includes propelling liquid to flow both axially centrally and transversely of said recesses and through propulsion zones in the recesses so as to draw liquid in first high velocity courses of flow from within the interior of said cleaning zone toward said recesses and so as to return liquid in second high velocity courses of flow away from said recesses toward the interior of said cleaning zone, directing the propelled liquid in streamlined flow pattern looping toward the interior of said cleaning zone from about said propulsion zones, periodically reversing the direction of liquid propulsion in one of said recesses at the ends of predetermined primary time intervals, and periodically reversing the direction of liquid propulsion in a recess opposite said one recess at the ends of predetermined secondary time intervals.

3. The method of claim 2 in which said secondary time intervals are twice as long as said primary time intervals.

4. The method of claim 2 including collecting soils entrained in said liquid below said cleaning zone.

5. The method of claim 2 including removing some of the liquid from said cleaning zone in a side stream, co1- lecting soils carried in said side stream, and returning said side stream of liquid to said cleaning zone.

6. The method of claim 2 including passing steam upwardly from said liquid and out of said cleaning zone.

7. The method of claim 2 including maintaining a seal comprising a second liquid overlying the liquid in said cleaning zone.

References Cited in the file of this patent UNITED STATES PATENTS 855,071 Smith May 28, 1907 1,034,229 Gribben July 30, 1912 1,161,621 Craven Nov. 23, 1915 1,409,271 Bartelt Mar. 14, 1922 1,783,194 McConnell Dec. 2, 1930 2,310,569 Booth Feb. 9, 1943 2,478,188 Gibson Aug. 9, 1949 

1. THE METHOD OF DISPLACING LIQUID WITHIN A CLEANING ZONE FORMED BY AN UPRIGHT RECEPTACLE HAVING RECESSES AT OPPOSITE INNER SIDES THEREOF OPENING OPPOSITELY TOWARD ONE ANOTHER TRANSVERSELY OF AND ACROSS SAID ZONE, SAID METHOD IMPROVING THE EFFECTIVENESS OF SOILS SEPARATION FROM SOLID ARTICLES PLACED IN SAID CLEANING ZONE, THAT INCLUDES PROPELLING LIQUID TO FLOW BOTH AXIALLY CENTRALLY AND TRANSVERSELY OF SAID RECESSES AND THROUGH PROPULSION ZONES IN THE RECESSES SO AS TO DRAW LIQUID IN FIRST HIGH VELOCITY COURSES OF FLOW FROM WITHIN THE INTERIOR OF SAID CLEANING ZONE TOWARD SAID RECESSES AND SO AS TO RETURN LIQUID IN SECOND HIGH VELOCITY COURSES OF FLOW AWAY FROM SAID RECESSES TOWARD THE INTERIOR OF SAID CLEANING ZONE, DIRECTING THE PROPELLED LIQUID IN STREAMLINED FLOW PATTERN LOOPING TOWARD THE INTERIOR OF SAID CLEANING ZONE FROM ABOUT SAID PROPULSION ZONES, AND PERIODICALLY REVERSING THE DIRECTIONS OF LIQUID PROPULSION IN FIRST AND SECOND RECESSES AT THE ENDS OF PREDETERMINED PRIMARY AND SECONDARY TIME INTERVALS RESPECTIVELY. 